Search results for "circulatory and respiratory physiology"
showing 10 items of 329 documents
Increased risk for venous thrombosis in carriers of the prothrombin G→A20210 gene variant
1998
A mutation in the prothrombin gene (G--A20210) has been associated with higher plasma prothrombin levels and an increased tendency for venous thrombosis.To determine whether the prothrombin A20210 allele is independently associated with the occurrence of venous thrombosis.Case-control study.Two thrombosis centers in southern Italy.281 consecutive patients with venous thrombosis confirmed by objective tests and 850 controls.Medical history was collected on standardized questionnaires. The presence of prothrombin G--A2020 and factor V Leiden mutations was determined by polymerase chain reaction. The presence of anticoagulant factors and prothrombin activity was determined by tests of function…
Relationship Between Regional Cerebral Blood Flow and Electrocorticographic Activities Under Sevoflurane and Isoflurane Anesthesia
2010
The aims of this study are (1) to assess the effects of volatile anesthetics on regional cerebral blood flow (rCBF) and electrocorticography (ECoG), and (2) to investigate the relationship between rCBF and ECoG influenced by volatile anesthetics. The authors measured rCBF using laser Doppler flowmetry and ECoG simultaneously and continuously from the same cortex during craniotomy, using the specially arranged probe. Patients received intravenous anesthetics with nitrous oxide until craniotomy, and after opening of dura, volatile anesthetic, either isoflurane or sevoflurane, was started and was gradually increased for the measurement. Four of the nine cases (44.4%) of the sevoflurane group s…
Airway Responsiveness to Inhaled Acetaldehyde in Subjects with Allergic Rhinitis: Relationship to Methacholine Responsiveness
2002
<i>Background:</i> Asthmatic subjects have an exaggerated airway response to inhaled acetaldehyde, but no information is available on airway responsiveness to this bronchoconstrictor agent in subjects with allergic rhinitis. <i>Objective:</i> The aim of this study was to determine the effect of inhaled acetaldehyde on lung function in nonasthmatic subjects with allergic rhinitis. <i>Methods:</i> A total of 78 adults (43 subjects with allergic rhinitis, 16 asthmatics and 19 healthy subjects) were challenged with increased concentrations of acetaldehyde and methacholine. The response to each bronchoconstrictor agent was measured by the provocative concentra…
Baroreflex control of heart rate during sleep in severe obstructive sleep apnoea: effects of acute CPAP
2006
Baroreflex control of heart rate during sleep (baroreflex sensitivity; BRS) has been shown to be depressed in obstructive sleep apnoea (OSA), and improved after treatment with continuous positive airway pressure (CPAP). Whether CPAP also acutely affects BRS during sleep in uncomplicated severe OSA is still debatable. Blood pressure was monitored during nocturnal polysomnography in 18 patients at baseline and during first-time CPAP application. Spontaneous BRS was analysed by the sequence method, and estimated as the mean sequence slope. CPAP did not acutely affect mean blood pressure or heart rate but decreased cardiovascular variability during sleep. Mean BRS increased slightly during CPAP…
The effect of challenge method on methacholine-induced changes in sensitivity and air trapping
2010
Summary Background The methacholine challenge test performed with the tidal breathing method induces a greater fall in FEV 1 than the dosimeter method; however, the effect of the challenge method on methacholine-induced fall in FVC has not been investigated. Objective To determine the influence of the challenge method on methacholine-induced changes in FEV 1 and FVC. Methods Airway responsiveness to methacholine was determined by dosimeter method and tidal breathing method in 37 subjects with suspected asthma. The dosimeter was modified to deliver an identical volume to that obtained with the tidal breathing method and the same nebulizer model was used for the two challenges. The response w…
The Lack of the Bronchoprotective and Not the Bronchodilatory Ability of Deep Inspiration Is Associated with Airway Hyperresponsiveness
2001
In healthy subjects, deep inspiration (DI) acts both as a bronchodilator and a bronchoprotector. The latter is impaired in asthmatics. We have now evaluated whether the lack of bronchoprotection is related to bronchial hyperresponsiveness (BHR), and whether the bronchodilatory effect is also lost in asthmatics. Ten healthy subjects (PC20 > 75 mg/ml), 12 asthmatics with moderate to severe BHR (PC20 < 1 mg/ml), 14 asthmatics with mild to borderline BHR (1 < PC20 < 25 mg/ml), and 10 rhinitics with mild to borderline BHR (1 < PC20 < 25 mg/ml) underwent single-dose methacholine provocations inducing at least 20% reduction in FEV1 after 20 min of DI inhibition. To measure the bronchodilatory effe…
Is it possible to predict which patients with mild pneumonias will develop hypoxemia?
2009
SummaryUsually, mortality due to mild community-acquired pneumonias (CAP) (Pneumonia severity index (PSI) classes I–III) is low (<3%), but the appearance of hypoxemia significantly increases mortality. Our aim was to determine the clinical parameters associated with risk factors of developing hypoxemia in subjects with mild CAP (PSI I–III) and the clinical outcomes of the hypoxemic group.We analyzed clinical characteristics and the outcomes of patients with mild CAP and hypoxemia (PaO2/FiO2<300), in a prospective, multicenter cohort study of 1195 patients.Mild pneumonias (PSI I–III) were found in 645 cases (53.9%), of which 217 (33.6%) presented hypoxemia according to a PaO2/FiO2<300. Patie…
Predicting hypoxia in cystic fibrosis patients during exposure to high altitudes
2006
Abstract Background For patients with cystic fibrosis (CF)-related partial respiratory insufficiency and reduced arterial oxygen tension at ground level, the mild hypobaric environment on commercial jet aircraft poses the risk of severe hypoxemia. Thus, physicians should be able to estimate the extent of in-flight hypoxia. Objectives To derive tools for estimating the expected drop in arterial oxygen partial pressure (paO 2 ) and oxygen saturation (saO 2 ) in young adult CF patients with mild to moderate airway obstruction during exposure to the hypobaric conditions aboard commercial aircraft and to test the predictive power of a hypobaric chamber simulation. Methods Blood gases of 12 CF pa…
Interaction of atenolol with furosemide and calcium and aluminum salts
1981
Six healthy subjects were treated with 100 mg atenolol. After a therapy-free interval of 4 wk the same subjects received the same dose of atenolol with furosemide, 40 mg, with calcium (as the lactate gluconate and carbonate), 500 mg, or with aluminum hydroxide, 5.6 gm. Atenolol alone and in combination was administered first as a single oral dose; a long-term 6-day treatment began 48 hr later. Addition of furosemide did not influence atenolol kinetics, but aluminum hydroxide led to an insignificant reduction (P greater than 0.05) of mean peak plasma levels of about 20% and of the area under the plasma concentration-time curve (AUC -infinity) from 5818 to 4353 ng ml-1 hr (P greater than 0.05…
Alteration of vancomycin pharmacokinetics during cardiopulmonary bypass in patients undergoing cardiac surgery.
2003
The alteration of vancomycin pharmacokinetics during cardiopulmonary bypass (CPB) in patients undergoing cardiac surgery was studied. Eighteen patients were enrolled in the study. Vancomycin (1 g) was intravenously infused one to two hours before surgery. Blood samples were taken before, during, and after CPB. Serum drug concentrations were determined by an automated fluorescence polarization immunoassay and adjusted, with a bayesian analysis, to a bi-compartmental model implemented in a pharmacokinetic system program. Serum creatinine, hematocrit, and plasma proteins were also measured before, during, and after CPB. During CPB, serum creatinine, hematocrit, and plasma protein values all de…